The invention relates to an apparatus for stirring and, respectively, or kneading dough, comprising a frame having a seat into which a receptacle for the dough can be inserted and in which the receptacle in its inserted position can be lifted by a lifting means along guide means into a position in which at least one tool carried by the frame for stirring and, respectively, or kneading the dough extends into the receptacle that cannot be rotated in this position, each tool being driven by a drive means carried by the frame to a revolving or kneading motion, at least one tool being eccentrically with respect to the axis of the receptacle supported within a tool carrier for relative motion with respect to it, which tool carrier being rotatable by a drive means relative to the receptacle around the axis thereof and in the lifted position of the receptacle forming a closure cover for the upper opening of the receptacle, and wherein the frame comprises a collar against which the edge of the upper opening of the receptacle is lifted for reaching its lifted position. Such an apparatus is known from GB-A 2 015 362.
Numerous apparatus are known for stirring or kneading of dough. The usual construction of mixing machines comprises a spiral member as the tool which is driven via the machine head, a machine support being lifted so that the mixing vat which can be separated from the apparatus frame, can be drawn out. Within other apparatus, the mixing head is not liftable in vertical direction, but can be swung open to the rear. Such apparatus have the advantage that the treated dough can be conveyed by means of the receptacle so that the dough can be transported to another working place of the bakery in a time-saving manner. Only within apparatus for treating smaller amounts of dough, the receptacle cannot be carried out but is stationarily fixed to the frame. If the tools necessary for treating the dough are not liftable, they hinder taking out the finished dough.
For a heavy industrial machine it is known to prepare the dough to be treated within a trough, kneading tools being horizontally disposed. For the discharge of the dough, the trough is tilted around a horizontal axis.
There is also known an apparatus in which a receptacle which can be carried by means of a chassis can be carried towards the frame into its seat and by a hydraulic means can be brought into the working position in which mixing tools disposed in the machine head engage into the receptacle (Prospectus Collette High Speed Mixers).
With the exception of the said heavy industrial machine, these known mixing machines have the disadvantage that the force flow leads via mixing tool, mixing machine support, connection thereof to the receptacle and via the dough mass again back to the tool. Therefore, all connection elements must be constructed very heavy and strong fixing means must be provided between receptacle and mixing machine support in order to meet the considerable forces created during mixing. Also the receptacles themselves must be constructed so strong that also their receptacle walls can meet the forces created. Nevertheless, in practice there again and again happen deformations, even if sometimes support rollers are provided on the support member, against which the wall of the receptacle is abutted for the purpose to avoid the said deformations.
The latter disadvantage is moderated within a construction of the initially described kind by bearingly supporting the tool carrier on a bridge bridging the collar of the frame. Thereby, the forces indeed to not flow via the receptacle, but the bridge increases the constructional height of the apparatus and considerable bending forces act onto rotational bearing of the tool carrier by the reaction forces introduced by the tool. The invention has at its object to design an apparatus of the initially described kind in which the said stresses are considerably moderated and in which, in comparison to the last mentioned known apparatus, the constructional height is reduced and the rotational support of the tool carrier is improved. Further, the invention has at an object to design an effective and versatile construction with respect to the treatment of the dough. The invention solves this task--starting from the initially described known apparatus--by the features that the tool carrier with its periphery is bearingly supported on the collar. Thereby, the reaction forces introduced from the tool or the tools are considerably more favourable diverted from the tool carrier to the frame as within the lastly described known apparatus and, in addition thereto, the constructional height is reduced by saving the bridge and the construction is simplified. Due to the fact that the support means for the tool carrier are transferred from its center to its periphery, there is also more space at disposal for accommodating the tools or their drive means. Therefore, the invention can also be applied to very great apparatus, i.e. for receptacles having a great capacity, where the reaction forces are correspondingly high. Therefore, the invention can also be used for such receptacles which due to their great weight must be carried on roller means. Preferably, within the spirit of the invention, the receptacle is provided with a chassis. This enables one to use several receptacles alternately, which must be changed very quickly. The receptacle which in operation, i.e. in its lifted position, is stationary, needs no effort for its drive means for rotation, what is of substantial advantage in particular for great machines due to the considerable weight of a large receptacle together with the dough mass contained therein. Fixing the receptacle in the operation position does not cause any problem and can be done without great power requirement in each rotational position of the receptacle which is of rotational-symmetrical shape, since the receptacle is not positioned in the flow of the forces. Further, the inventive apparatus is variable with respect to the tools used and the already mentioned space which is substantially at disposal on the tool carrier, enables a stable bearing of all tools used.
Also the advantage given within the lastly described known construction is maintained that the tool carrier in the lifted position of the receptacle constitutes a closure cover for the upper opening of the receptacle so that an unintentional escape of dough or dough portions is avoided in a simple manner.
According to a preferred embodiment of the invention, the tool carrier extends like a pot into the collar from above and is bearingly supported for rotation with a cylindrical wall by means of a bearing on an also cylindric wall of the collar. This results in the most favourable construction for deviating the reaction forces into the frame.
According to a further embodiment of the invention, separate drive means are provided for the rotational movement of the tool carrier and for the movement of the tools relative to it. This is more favourable than a construction in principle also possible, which deviates the movement of the tool carrier and the movement of the tools frome the same driving motor, for example by means of a planetary gear carried by the tool carrier. However, using separate drive means enables one to adjust the movement of the tools completely independent from the rotational movement of the tool carrier and optionally to change the tool movement during the treating process without that this has any influence upon the rotational movement of the tool carrier. It is of particular advantage within the spirit of the invention, if the tool carrier carries a gear means for the movement of the tools which comprises a driving shaft being positioned in the axis of the receptacle, which shaft being driven by a motor carried by the frame, preferably by means of a V-belt. This results in a particular simple and favourable construction, the gear means enabling one to adjust the speed of revolution of the tools to the respective desired requirements.
As already mentioned, the invention is versatile with respect to the kind of the tools used which must not necessarily rotate around their own axes, but may also be kneading tools, which move like a pendulum. In the first named case, the tool carrier according to the invention is provided with at least one opening in its bottom which is disposed eccentrically with respect to the axis of the receptacle and is penetrated by the shaft of a tool extending towards the axis of the receptacle, preferably using a bearing, this shaft being a driving shaft of the gear. For kneading tools, it is possible within the spirit of the invention to provide the tool carrier in its bottom with at least one slot penetrated by a tool which on its upper end is linked to a crank on the driven shaft of the gear and at a lower location is linked to a connecting rod articulated to the tool carrier. Suitably, according to the invention the remaining portions of each slot are covered by a bellow member for the purpose to avoid an, undesired escape of material to be treated from the receptacle. Within such a construction it is suitable to provide at least two tools which at each moment have different operation positions in order to optimally treat the dough. It is particularly favourable within the spirit of the invention to link always two tools to two cranks which are driven in opposite direction.
The inventive apparatus is comparatively insensitive to the relative position of the tools with respect to the receptacle. However, for practical reasons and for the purpose of avoiding undesired tensions in the receptacle it is suitable to anchor the receptacle in the lifting device which is known per se, in a particular manner. For this, a further embodiment of the invention provides that the lifting device comprises a fork between the legs thereof the receptacle can be carried in and on which a clamping device for the uper edge of the receptacle is provided. According to a further embodiment of the invention, this clamping device comprises at least two bows overlapping the rim of the receptacle, which bows in the lifted position of the receptacle are pressed by springs against the rim of the receptacle, however in the carrying-in position engage stops by means of protrusions and in this position are lifted against the action of the springs, leaving free the rim of the receptacle. Within this, an automatic centering can be obtained by providing the bows and respectively, or the rim of the receptacle with oblique surfaces for centering the receptacle.